Recreational and sport fishing has great global markets. Millions of anglers are counted throughout the world and their number is still growing. The invention described in this document relates closely to fishing with a lure or e.g. a baited hook trolled behind the boat. The number of trolling anglers in Europe, the USA and Canada is estimated to be over 40 millions. Typically, the anglers are fishing for a specific species and it is known that fish are active in varying temperatures species-specifically, as can be seen in FIG. 1, and also the richest area of various species in general may be determined.
However, while fishing for particular species, the control over the depth of the lure in water is a major problem. Typically, the means that the anglers are using for depth control is such as a downrigger, see FIG. 2 and entity 202 therein, a submersible temperature/depth transducer and monitor and a diver. Alternatively, the depth of the lure can be controlled by different lure types or by adjusting the length of the fishing line and trolling speed. A downrigger, which is bolted to the stern of a fishing vessel, consists of an electrical or mechanical reel and a short rod. The reel is filled with strong line\wire, which is attached to a lead weight. A submersible temperature/depth transducer and monitor, attached to the downrigger line instead of a conventional weight, is used for reading the temperature and speed through a coaxial cable to the LCD screen located in a boat. However, the handling of a downrigger is difficult and usually, when the fish strikes, one more person is needed to wind up the downrigger. Further, a small disk known as a diver is attached to the fishing line to make a lure dive deeper. Any of the means mentioned above are merely adapted to track a predetermined depth disregarding various other factors truly affecting the actual position of fishes. In addition, e.g. a downrigger with a submersible temperature/depth transducer and monitor is an expensive piece of equipment and yet, a depth chart is also needed. Moreover, the diver is generally not accurate and it does not offer any method of measuring the temperature in real time.
U.S. Pat. No. 6,760,995B2 discloses a submersible device for controlling the depth and the azimuth heading of the device. However, the publication mainly concentrates on the remote control part of the suggested arrangement despite the cursory disclosure of sensors for sensing the characteristics of the underwater environment.
Thus the objective of the present invention is to at least alleviate the aforesaid defects of prior art solutions when it comes to the usability and fish tracking capability thereof.